CaAl包芯线的熔化特征及喂线参数的优化

模拟研究了1873 K钢液温度下钢皮厚度0.74 mm的Ca Al包芯线的熔化、气化行为及150 t钢包的理想喂线参数, 并试验研究了不同钢种及钙合金包芯线对钙收得率的影响.结果表明:包芯线喂入钢液后, 包芯线的Ca Al合金先于包敷的钢皮熔化, 自喂入钢液0.92 s后, 包芯线顶端钢皮熔化, 液态Ca Al合金进入钢液后扩散溶解, 当钙液滴上浮到钢液面以下1.22 m深度时, 达到了气化的饱和蒸汽压, 才会气化.在150 t钢包条件下, 为了减少钙的气化烧损, 采用3.22⁴.83 m·s^-1的喂线速度, 实现包芯线在钢液深度2.96 m处熔化的目标.为了提高钙的收得率, 应采用纯钙包芯线处理碳、硅、锰等元素含量较高的钢种, 选择Ca Al包芯线处理低硅低锰的低碳钢种.     

喂SiCaBa包芯线对钢中夹杂物变性的影响

为了使钢中的夹杂物更好的变性,在250kg非真空感应炉上,对冷镦钢进行了Al和FeSiAl脱氧后喂SiCaBa包芯线的研究,并作了喂SiCa包芯线的对比实验。结果表明,喂SiCaBa包芯线的效果优于喂SiCa包芯线。表现在:能够较快地使钢液的全氧含量达到平衡;钢液的全氧含量和夹杂物面积均有所下降;脱氧产物由Al2O3变为mCaO·nAl2O3或者CaO Al2O3 SiO2复合夹杂物,并近乎完全球化。     

钢包喂实芯纯钙包芯线的工业性试验研究

概述了在杭钢转炉炼钢厂50t钢包中,进行喂实芯纯钙包芯线试验情况。试验表明其冶金效果和经济效益显著,与原喂硅钙相比:钙平均收得率大幅度提高到25.4%;钙处理成本降低了7.3元/t。喂线速度是影响钙收得率的主要参数,从理论上探讨了为了提高合金收得率,在本试验条件下,50t钢包的理论喂线速度Ve=1.29m/s,与试验的数据基本一致。由于喂实芯纯钙包芯线的特殊性,提出了其供钙速度应控制在0.09~0.11kg/t.min之间。     

钢液喂Ca-Si包芯线的钙收得率研究

钙处理是将钢液脱氧、脱硫到极低水平的重要方法。此外,通常用钙来控制氧化物、硫化物夹杂的形状、尺寸和分布。所获得的含钙夹杂物即使经过后续的热加工操作之后仍将保持其球形。因而防止了链状氧化铝、硫化物的形成,产品性能的各向异性得以大幅度减小,尤其是可提高产品厚度方向的延     

LF喂Ca线改善易切削钢Y1Cr13硫化物形貌的工艺实践

试验钢Y1Cr13(/%:0.11C,0.31Si,1.14Mn,0.024P,0.28S,12.43Cr,0.001 1Ca,0.012Al,0.008 40,Mn/S 4.07)的冶金流程为60 t AOD-LF-150 mm×150 mm坯连铸-轧制Φ12 mm材。原未加Ca的LF精炼渣碱度为1.7～2.1,用Fe-Si脱氧,T[0]为0.012%～0.015%,而改进的加Ca工艺为LF FeSi脱氧后补加Al线深脱氧,T[O]为0.007%～0.010%,加Ca线进行夹杂物变性处理。结果表明,加入实芯钙线使钢中长条型硫化物变性为球型或纺锤型,线材产品中硫化物长度由最长的160μm缩短为100μm,纺锤形硫化物(长宽比≤3)所占比例由52.90%提高至72.09%,提高了产品切削性能。     

钢包喂Ca—Si线对钢中夹杂物变性的影响

在实际的铝镇静钢生产工艺条件下,对钢包内钢水喂Ｃａ－Ｓｉ线处理后夹杂物的组成、形态、尺寸和分布等的变化规律作了了详细的研究。结果表明,喂线后钢中钙、铝比达到０．０９以上时,钢中的Ａｌ２Ｏ３类夹杂物能获得较好的变性;夹杂物中的钙、铝比随喂线后钢中钙、铝比的增大线性增加;钢中较高的钙、铝比有利于连铸坯中大颗粒夹杂物的去除,有利于夹杂物球化率的提高。     

气体旋流喂丝枪喂椭圆包芯线实现钢液内部喂丝钙处理

介绍了钢包中钢液钙处理的起源及钙的加入方法和研制的气体旋流喂丝枪和高致密椭圆截面包芯线。建议包芯线成形机和喂丝机生产企业借鉴焊管成形机进行技术改造,生产椭圆截面包芯线成形机;将圆拄面齿形喂丝轮改造成圆弧槽喂丝轮;钢铁企业喂丝处理时增加活动导丝管升程,以实现钢液内部喂丝钙处理。     

LF喂Si-Ca线对X70管线钢夹杂物变性的影响

100 t BOF-LF-RH-CC流程冶炼X70管线钢[%:0.04C、1.53Mn、0.106(Nb+V+Ti)],并在LF精炼时采用喂Φ13 mm 60Si-28Ca线处理。经计算和生产试验得出,喂线速度由100 m/min提高至200 m/min时,平均钙收得率由4.05%提高至14.93%,以200 m/min喂入Si-Ca线420～500 m时满足硫化物变性要求,铸坯中69%夹杂为2～10μm球形或类球形夹杂,且处在CaO-Al₂O₃-MgO系相图低熔点区,变性效果好。     

实芯纯钙线在LF精炼过程中的应用

对比分析了实芯钙线(99.35%Ca)和钙铁线(30.53%Ca)在160 t、230 t和300 t LF精炼过程应用的冶金效果。喂纯钙线前后平均钢水的酸溶铝、硫含量和温度分别为0.036%、0.010%、1 587℃和0.029%、0.008%、1584℃。与喂钙铁线相比,喂实芯纯钙线,钙的收得率提高10%,喂线量少50%,喂线时间缩短2～3 min,钢水温降减少3～5℃,具有明显的冶金效果。     

150 t LF精炼喂钙线处理钢中夹杂物的演变

通过热力学计算和扫描电镜研究了铁水预处理-150 t BOF-钢包吹氩-LF-CSP流程LF精炼后喂硅钙线和钙铝线处理的Q235,SPA-H和DC01钢中夹杂物演变及精炼渣对其影响。结果表明,Ca处理前的精炼过程中,钢中Al₂O₃大部分已经被精炼渣（/%:52.97~55.63CaO,4.11~12.78SiO₂,5.11~9.87MgO,22.93~31.72Al₂O₃,0.58~1.27FeO,0.01~0.07MnO）改性为MgO·Al₂O₃,根据Mg-Al-O生成优势区图,钢中有微量Mg就能使Al₂O₃变性为MgO·Al₂O₃尖晶石,钙处理主要是对MgO·Al₂O₃尖晶石的变性,因此需要保证充足的钙线喂入量,才能将高熔点铝镁和铝镁钙复合夹杂物变性到低熔点区域;为了避免生成高熔点CaS夹杂物,钙处理前[Al]=0.02%~0.04%时,[S]要小于0.001 4%。      

纯钙包芯线在转炉炼钢中合金替代的研究

为了降低转炉炼钢工序的合金消耗,在莱芜钢铁集团有限公司炼钢厂120t、60t、80tLF精炼炉上进行了纯钙包芯线合金替代试验。转炉炼钢过程中使用纯钙包芯线进行钢水钙处理,钙平均收得率达到了16.02%～31.42%的好效果,试验证明,纯钙包芯线作为钙处理剂能成功替代钙铁线和硅钙线。     

Dissolution Kinetics of Cored Wire in Molten Steel

An essential feature in steel refining is the injection of calcium in the steel ladle in the form of a cored wire for de‐oxidation and inclusion modification. The melting behaviour of these cored wires has an important influence on the efficiency of the injection process, castability of steel and the product quality. The calculation of the time for melting of the casing of the cored wire and the subsequent release of the filling materials into the bath cannot be done without resorting to an elaborate mathematical model due to the complexity of the heat transfer from the bath to the wire. In particular the formation of a solid shell around the wire and consequent lowering of the heat transfer needs to be addressed accurately. A mathematical model for calculating the melting time of the casing has been developed at R & D, Tata Steel. This model describes the freezing and melting process during the travel of the cored wire in the steel bath. The model has been validated against published data. Owing to the complexity of obtaining a direct validation, a novel indirect method has been adopted. The variation in the operating conditions demands variation in the cored wire parameters to make the injection process equally efficient under all conditions. The model has also been used to formulate the specification of cored wire to suit the injection temperature of different grades of steel.     

钙铁包芯线的制作及其在钙处理中的应用

介绍了钙铁合金包芯线制作中质量控制要点,需要采用钙铁线进行钙处理钢的品种特点及其成分控制要求,总结了对钢水进行钙处理精炼中的工艺技术要求。     

Effectiveness of Alloying Steel with Vanadium from Cored Wire

An analysis is made of the distribution and assimilation of vanadium in finished steel. It is shown that the character of assimilation of vanadium is unstable when lump ferrovanadium is used. Given the same consumption of ferrovanadium per heat, the scatter of vanadium content is 0.007–0.18% (abs.) or 20.6–37.5% (rel.). The alloying of steel by cored wire filled with a vanadium-aluminum master alloy (72.9% V and 26.5% Al) results in a consistently high level of vanadium assimilation – 98.7%. The minimum level of assimilation in this case is 90.1%.     

复合纯钙铝线在LF精炼炉的应用实践

为保证精炼过程钙处理效果,降低生产成本,福建三钢引进了复合纯钙铝线进行试验.试验表明,复合纯钙铝线的经济效益显著,与喂钙铝包芯线相比:钙的回收率提高16％,吨钢综合成本降低了2元,且大大降低了喂线过程中卡线,断线等异常情况.